Redesigning donor–acceptor Stenhouse adduct photoswitches through a joint experimental and computational study

Berraud-Pache, Romain; Santamaría-Aranda, Eduardo; Souza, Bernardo de; Bistoni, Giovanni; Neese, Frank; Sampedro, Diego

doi:10.1039/d0sc06575g

Cited by 23 publications

(27 citation statements)

References 44 publications

(74 reference statements)

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“…This kinetic behavior is in line with a two‐step mechanism, which involves a light‐triggered Z/E photoisomerization ( oD 0 ⇆ oD’ ) followed by a cyclization resulting in the cyclic colorless form ( oD’ ⇆ cD ) (Scheme S2). Such behavior is in line with what previously described [20–24] . In order to quantitively extract the rate constants and the UV‐Vis absorption spectrum of oD’ for the DASAs , we developed and used a three‐state kinetic model (Figure S3e, Table S4, and section 5 of Supporting Information).…”

Section: Resultssupporting

confidence: 79%

“…Such behavior is in line with what previously described. [20][21][22][23][24] In order to quantitively extract the rate constants and the UV-Vis absorption spectrum of oD' for the DASAs, we developed and used a three-state kinetic model (Figure S3e, Table S4, and section 5 of Supporting Information). In contrast with what observed for DASA1 and DASA3, but in line with what previous reported, [6] the trifluoromethyl derivatives (DASA4, DASA5) do not exhibit any significant photoisomerization (Figures S5, S6).…”

Section: Photoisomerization In Organic Solventsmentioning

confidence: 99%

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Unexpected Acid‐Triggered Formation of Reversibly Photoswitchable Stenhouse Salts from Donor‐Acceptor Stenhouse Adducts

Shpinov

Schlichter

Pelupessy

et al. 2022

Chemistry A European J

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Donor-acceptor Stenhouse adducts (DASAs) are reversibly photoswitchable dyes, which are able to interconvert between a red/NIR absorbing triene-like state and a colorless cyclic state. Although optically attractive for multiple applications, their low solubility and lack of photoswitching in water impede their use in aqueous environments. We developed water-soluble DASAs based on indoline as donor and methyl, or trifluoromethyl, pyrazolone-based acceptors. In acetonitrile, photophysical analysis and photochemical studies, accounted with a three-state kinetic model, con-firmed the reversible photoswitching mechanism previously proposed. In water, the colorless cyclic state is a thermodynamic sink at neutral pH values. In contrast, in acidic conditions, we observed a fast scrambling of DASAs' endgroup resulting in the in situ formation of Stenhouse salts (StS), which are in turn capable of reversible photoswitching. We believe that this unexpected result is of interest not only for the future design of DASAs with improved stability, but also for further development and applications of StS as photoswitchable probes.

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Section: Resultssupporting

confidence: 79%

Section: Photoisomerization In Organic Solventsmentioning

confidence: 99%

Unexpected Acid‐Triggered Formation of Reversibly Photoswitchable Stenhouse Salts from Donor‐Acceptor Stenhouse Adducts

Shpinov

Schlichter

Pelupessy

et al. 2022

Chemistry A European J

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“…[ 8–10 ] DASAs undergo a visible light‐induced, colored to colorless, open triene to closed cyclopentenone isomerization that is thermally reversible. [ 11–15 ] Their tunable absorption in the spectral range between 450 and 750 nm [ 16–21 ] enables DASA activation at wavelengths suitable for biological applications. [ 22 ] DASA‐functionalized polymers were already investigated for potential applications in a number of areas ranging from photo‐/hydrochromic, [ 23–25 ] photopatternable, [ 26–29 ] or wettability switching [ 30–34 ] surfaces and objects, to smart drug delivery, [ 35–40 ] chemical sensing, [ 41–45 ] and photoactuation.…”

Section: Introductionmentioning

confidence: 99%

Donor–Acceptor Stenhouse Adduct‐Polydimethylsiloxane‐Conjugates for Enhanced Photoswitching in Bulk Polymers

Clerc

Tekin

Ulrich

et al. 2022

Macromol. Rapid Commun.

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Donor-acceptor Stenhouse adducts (DASAs) are a rapidly emerging class of visible light-activated photochromes and DASA-functionalized polymers hold great promise as biocompatible photoresponsive materials. However, the photoswitching performance of DASAs in solid polymer matrices is often low, particularly in materials below their glass transition temperature. To overcome this limitation, DASAs are conjugated to polydimethylsiloxanes which have a glass transition temperature far below room temperature and which can create a mobile molecular environment around the DASAs for achieving more solution-like photoswitching kinetics in bulk polymers. The dispersion of DASAs conjugated to such flexible oligomers into solid polymer matrices allows for more effective and tunable DASA photoswitching in stiff polymers, such as poly(methyl methacrylate), without requiring modifications of the matrix. The photoswitching of conjugates with varying polymer molecular weight, linker type, and architecture is characterized via time-dependent UV-vis spectroscopy in organic solvents and blended into polymethacrylate films. In addition, DASA-functionalized polydimethylsiloxane networks, accessible via the same synthetic route, provide an alternative solution for achieving fast and efficient DASA photoswitching in the bulk owing to their intrinsic softness and flexibility. These findings may contribute to the development of DASA-functionalized materials with better tunable, more effective, and more reversible modulation of their optical properties.

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“…The control of the properties has been mainly introduced by the modification of the donor and acceptor moieties to prepare different generations of DASAs. 9 However, the triene π-bridge also has the potential to alter the thermal steps of the mechanism and modify some of the properties. This approach has been less explored for the change in the ends of the DASAs due to practical reasons.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the Aza-Piancatelli Reaction: Scope and Limitations of Furan Substitution in Donor–Acceptor Stenhouse Adduct Synthesis

et al. 2022

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The aza-Piancatelli reaction has been widely used to synthesize donor–acceptor Stenhouse adducts (DASAs), a new class of molecular photoswitches with unique properties. However, the substitution pattern of furan cores has been limited to position 3, as 3,4-disubstituted furans remain unreactive. Herein, we explore the aza-Piancatelli reaction mechanism using density functional theory (DFT) calculations to understand the influence of the different substituents on the reactivity. We found that all the reaction pathways are kinetically accessible, but the driving force of the reaction is lost in disubstituted furans due to the loss of conjugation in the DASA products. Finally, a simple model is proposed to guide the design of synthetic routes using this reaction.

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Redesigning donor–acceptor Stenhouse adduct photoswitches through a joint experimental and computational study

Abstract: New photoswitch Donor–Acceptor Stenhouse Adducts (DASAs) have been synthesized thanks to accurate computational chemistry predictions. They possess good properties, notably red light activation.

Cited by 23 publications

References 44 publications

Unexpected Acid‐Triggered Formation of Reversibly Photoswitchable Stenhouse Salts from Donor‐Acceptor Stenhouse Adducts

Unexpected Acid‐Triggered Formation of Reversibly Photoswitchable Stenhouse Salts from Donor‐Acceptor Stenhouse Adducts

Donor–Acceptor Stenhouse Adduct‐Polydimethylsiloxane‐Conjugates for Enhanced Photoswitching in Bulk Polymers

Mechanism of the Aza-Piancatelli Reaction: Scope and Limitations of Furan Substitution in Donor–Acceptor Stenhouse Adduct Synthesis

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